Design of Rate-Compatible IRA Codes for Capacity-Approaching with Hybrid ARQ

We consider the design of efficient rate-compatible (RC) irregular repeat accumulate (IRA) codes, a subclass of LDPC codes, over a wide code rate range. The goal is to provide a family of RC codes to achieve high throughput in hybrid automatic repeat request (ARQ) scheme for high-speed data packet wireless systems. We focus on a hybrid design method which employs both puncturing and extending. We propose a simple puncturing method based on minimizing the maximal recoverable step of the punctured nodes and a new extending scheme by introducing the degree-1 parity bits for the lower rate codes and obtaining the optimal proportions of extended nodes through density evolution analysis. Simulation results show that our designed RC codes offer good error correction performance over a wide rate range and provide high throughput, especially in the high and low SNR regions